Electric motors, like any other machine or device, are subject to wear, malfunction, and breakage. Some electric motors, such as starter motors, are typically powered by a battery to start an internal combustion engine such as a car engine. When a starter motor does not operate properly it may be difficult or impossible to start a car. Thus, a starter motor can have an important impact on the reliability of an automobile. Accordingly, it is desirable to test starter motors from time to time to ensure their proper function, so that problems can be detected and corrected before a starter motor is working so poorly as to not be able to start the internal combustion engine of an automobile.
A large variety of conditions can cause a starter motor to not work properly. For example, there may be a short in the winding. The motor may be operating with a shorted winding due to a breakage or some other fault. Other causes for a malfunctioning motor may include a worn bearing within the motor. These, and other conditions, may cause a starter motor to not operate properly when subjected to a starter current. When a starter motor is not working properly, the motor may simply not operate at all or may operate at reduced revolutions per minute (RPM). If the starter motor is unable to apply the proper RPM to the internal combustion engine, the internal combustion engine may not start, thus, reducing the reliability of the automobile.
Currently, some ways of testing starter motors include applying a voltage to a starter motor and measuring the amount of current associated with the starter motor. If a current level is too high a tester may suspect that there is a short within the motor. Other test methods include observing the RPMs generated by the starter motor. Observing the RPMs generated by a starter motor may include a technician listening to the motor and determining whether the start motor “sounds” right. However, this type of testing may be relatively imprecise and may lead to deeming a malfunctioning starter motor as acceptable. Some problems may go undetected within the starter motor using starter motor test methods presently used. Accordingly, it is desirable to provide a convenient and effective method and apparatus for testing starter motors and determining their operability.